Clamp rings are used in brake actuator products and are typically made from sheet steel or other types of metal. Clamp rings may be used to contact and to hold the brake actuator housing parts together to keep pressure within the actuator housing. Clamp rings may also be used to reduce the lateral movement of the piston member and may be used to seal the actuator housing during operation of a brake actuator.
For clamp rings made of sheet steel, in the prior art, the steel is typically cut into strips of a width necessary to provide enough material to blank a round piece ranging from roughly six (6) inches in diameter to roughly ten (10) inches in diameter.
In prior art manufacturing processes, the following steps are provided. Step 1 involves a sheet steel of the correct thickness being provided. In step 2, blank round circles are formed in the steel sheet and anything outside of the circles is scrap which is thrown out and discarded. Step 3 involves drawing the circles into a basic shape and step 4 involves blanking out the center of the circles to form the ring, whereby the center of the circle is thrown away as scrap.
The prior art manufacturing process is shown in FIGS. 1-4. FIG. 1 shows steel sheet 100 of the correct thickness being provided. FIG. 2 shows blank round circles 205, 210, 215, 220 and 225 in the steel sheet 100. The blank is made as the steel around the circular ring is first scrapped blank.
FIG. 3 shows the step of drawing circles 300 to a basic shape and FIG. 4 shows the center 400 of the circle 300 blanked out. The center 400 is then scrapped and the clamp ring is formed.
The circular ring may also be passed through additional draw operations during this process. Such a process, however, is inefficient and wasteful as over 70% of the steel sheet is thrown away as scrap. Additionally, the end product clamp ring is generally weak as its side walls have been stretched during the manufacturing process. This is because the drawing process also reduces the thickness in the center of the vertical side of the ring due to the stretching inherent with the drawing process, and this results in clamp rings that have decreased tensile strength. Clamp rings that have decreased tensile strength have a shorter lifespan and are more likely to fail than clamp rings that do not undergo stretching or any other such tension or stress during the manufacturing process. In the prior art, a typical part as currently produced has a 15-20% sidewall thinning due to the drawing process from the base steel thickness.
Furthermore, the prior art process is inefficient as the cost of the clamp ring part includes the cost for the entire steel sheet including the scrap, which is removed. It is a huge waste of cost of materials to throw away the remainder of the steel sheet, while only a small portion of the sheet is used to form the clamp ring.
Clamp rings have been used on actuator products for years, and prior art attempts have been made to reduce the cost several times, however, each time a large percentage of scrap was required to make each part.
U.S. Pat. No. 6,526,867 (Anderson) teaches an annular retaining member formed by metal that can be made of either one or two pieces. However, the '867 patent teaches attaching the halves by a hinge, rather than by welding. The '867 patent further does not teach a process for manufacturing a clamp ring and does not mention the benefits of establishing a manufacturing process that eliminates and reduces waste scrap.
U.S. Pat. No. 5,775,202 (Plantan et al.) teaches a deformed clamp band made from a continuous roll. However, the '202 patent does not teach the process of welding the ends together. Furthermore, this patent does not teach a process for manufacturing a clamp ring and does not mention the benefits of establishing a manufacturing process that eliminates and reduces waste scrap.
U.S. Pat. No. 5,433,138 (Choinski et al.) and U.S. Pat. No. 5,311,809 (Choinski et al.) teach a retaining member comprising a ring of metal, but do not teach a process for manufacturing a clamp ring and do not mention the benefits of establishing a manufacturing process that eliminates and reduces waste scrap.
Similarly, U.S. Pat. No. 5,193,432 (Smith) teaches that one end of an annular retaining member can be butt welded to the other end. However, the '432 patent does not mention the benefits of this process for eliminating and reducing waste scrap. United States Patent Application No. 2004/0041007 (Cremerius) teaches a method of producing a strip portion, bending the strip portion to form a cylindrical ring with abutting strip ends and welding the strip ends so that they form a clamped ring. However, the '007 application does not mention the benefits of this process for eliminating and reducing waste scrap. Furthermore, both these patents do not teach a process for manufacturing a clamp ring and do not mention the benefits of establishing a manufacturing process that eliminates and reduces waste scrap.
As none of the prior art teaches a method and process for manufacturing a clamp ring that that eliminates and reduces waste scrap, it is desirable to provide such a method and process.
It is further desirable to provide a method and process for manufacturing a clamp ring without being inefficient and wasteful and without throwing out over 70% of the steel sheet as scrap material.
It is further desirable to provide a clamp ring that has an increased tensile strength because it does not undergo stretching the sidewall of the ring during manufacturing. It is further desirable to provide a clamp ring that has a seam formed by the metal joining technique.